For parties engaged in a voice or multimedia call it is often desirable to obtain call-related information while the call is still ongoing. Such call-related information may include the name and address of one of the parties or geographical information leading the way to one of the parties (e.g. map or route information). In order to initiate an in-call inquiry, one of the parties involved in the call will first enter a service request possibly including an identifier of the requested information in his or her user terminal. This service request will then be transferred to a network server hosting the requested information.
To a limited extent, current telephone networks already provide mechanisms for generating in-call service requests. One possibility that can be mentioned in this regard is the Short Message Service (SMS) well-known from conventional Global System for Mobile communication (GSM) networks. A Short. Message is compiled by operating the keyboard of the user terminal (typically by manually typing in a character sequence). It is, however, error prone and cumbersome for a user to type in a Short Message while being engaged in a call.
Somewhat more user-friendly is the generation of service requests using Internet browsers. Today, General Packet Radio Service (GPRS) and Universal Mobile Telecommunication System (UMTS) networks provide browsing functionalities also for mobile devices such as mobile telephones or personal digital assistants. Nevertheless, operating an Internet browser while talking on the telephone is disturbing and time consuming.
Another possibility for generating in-call service requests are Interactive Voice Response (IVR) systems. In an IVR system, a voice or tone recognition mechanism transforms audible user input into an electronic service request The use of an IVR system is generally unpractical for requesting in-call services as the user will have to place the ongoing call on hold while being connected to the IVR system.